Underground Market

Put an auction counter on target creature you
control, Choose an opponent: That player bids
an amount of life. In turn order, each opponent
may top the high bid. The bidding ends if the
high bid stands. The high bidder loses life equal
to the high bid and gains control of the creature
of his choice with an auction counter on it.
Whenever an opponent bids life, create a
colorless artifact token named Gold.